1. Field of the Invention
The present invention relates to detection patterns for detecting displacement of a probe at the time of probing in a semiconductor device having a plurality of IC chips formed of elements such as a transistor and a pad for probing formed on a silicon substrate.
2. Description of the Related Art
Conventionally, a probing test is generally carried out on an ordinary IC for checking electrical characteristics of a complete product.
Further, minimizing intervals between pads used in a probing test enables chip size reduction in an IC having many pads, and is indispensable to reduce IC cost.
In the probing test, which is often carried out with a thin detection needle, effect of displacement of the needle is larger in an IC having many pads for probing since the pad interval is small. Not only horizontal displacement of the needle in probing but also an inappropriate state of the needle in a depth direction (position or depth of entry of the needle) may prevent acquisition of correct electrical characteristics. Accordingly, in the probing test, detection of the displacement of the probing needle at the testing site is desirable in order to determine whether the test is carried out appropriately or not. A Japanese patent application JP 6-45419 A, for example, discloses a technique in which pads for detecting displacement of a needle at a time of probing is provided to carry out a measurement.
As described in the above, however, effect of displacement of the needle is larger in an IC having many pads for probing since the pad interval is small, resulting in the problems of inaccurate probing test, and capture of erroneous characteristics, and the like. In order to solve these problems, for example, a technique has been disclosed where a plurality of special pads for detecting displacement of a needle in operation are provided while carrying out measurement. However, such technique has problems of the large occupation area for pads, inability in detecting the direction of the displacement, inability in acquiring information along the depth direction, and the like.